TestFlight Unavailable message but latest version is already installed

Question

Have noticed a weird forced upgrade issue with TestFlight. Opening the app and it shows the Welcome to TestFlight intro screen, and pressing Continue shows an alert with the message:

TestFlight Unavailable
We've release a new version of
TestFlight. Download the update in the
App Store to continue testing.

However, opening the App Store, the latest version appears to be already installed (shows the Open button).

This is on iOS 10.3.3

Answer 1

I've run into this before, looks like TestFlight isn't auto updating from the app store. Was able to get it working again by uninstalling and re-installing TestFlight from the app store.

Hope this helps